Through-Hole Assembly

Posted:06:49 PM December 03, 2019writer: ​NextPCB

The through-hole assembly is a method of mounting electronic components on the printed circuit board, which is usually called through-hole technology (THT) or through-hole mounting (THM). This method of assembly replaced earlier electronic installation technology when the second-generation computers came out in the 1950s and held an absolute position in the installation process of components until surface-mount technology (SMT) appeared in the later 1980s. Although SMT is very popular now, the through-hole assembly still has a position in some applications. Let' s read the words below and take a closer look at through-hole technology.

What is the through-hole mounting technology for PCB assembly?

In the beginning, PCBs had only one side of the circuit, the through-hole mounting technology is the way of inserting the electronic components into the holes pre-drilled on the PCB and soldering them to the copper on the tracked side of the board by using leads. With the development of PCBs, there are tracks printed on both sides, and then the multiplayer is widely used. For connecting with the specific conductive layer effectively, through-hole develop into plated-through holes(PTH), which make it possible to connect components to traces on the inner layer of a printed circuit board.

The advantages and disadvantages of through-hole mounting technology for PCB assembly.

Though it seems the SMT has become the dominant method of PCB assembly, the fact is that through-hole technology is still a better choice for some specific devices and applications. The main reason is that THT offers more reliability and resiliency in even the most stressful environment due to their stronger connection between the electronic components with the board by using leads to pass through the holes. Therefore, heavy-type, high-power, or high –voltage components such as transformers are better to be installed by through-hole technology to ensure their mechanical and high-temperature resistance.

Through-hole assembly components are optimistic for the products which may experience extreme acceleration and high temperature or collisions. That' s why they are very popular in the automotive, aerospace, and military industries. Through-hole assemblies are also available for prototyping and testing because they are relatively easy to be adjusted or replaced.

At the same time, the disadvantages of through-hole assembly are apparent. Because of using components with wires or metallic leads to connect with PCBs, through-hole technology is very difficult to shrink the volume of the PCBs when the circuit is dense to a certain extent. The size of PCBs will limit the application range, and it is hard to meet the demands of less volume and simple design in most consumer electronics. What's more, drilling holes has a higher requirement for PCB design and will lead to a high investment in time and cost. The available wiring area becomes less due to the leads, especially in the multilayer PCBs, it is difficult to eliminate the trouble caused by the close leads and interference caused by the lead length. What' s more, most through-hole mounted components need to be placed by hand, which increases human input.

The through-hole technology for PCB assembly is significant in its way. Customers can choose the appropriate solution according to the specific applications. Please contact the online service in NextPCB without hesitate if it is hard to decide, experienced engineers will give you the best help to solve your problems.